The present invention relates to a wearable device and system to collect biological information of a user to monitor his or her metabolic state and calculate a calorie consumption.
As needs for enhancing health of middle-aged and elderly people and for preventing life-style related diseases have been growing in recent years, there is an increasing call for a user to be able to easily check his or her metabolic energy (energy consumption or calorie consumption) in a daily life for use in his routine health care.
For such a healthcare support, there has been a device that is worn by the user at all times to monitor a calorie consumption.
For example, an “energy consumption estimation device” described in JP-A-2005-230340 estimates an energy consumption (calorie consumption) from a walking speed and an inclination angle both calculated based on measurements of an acceleration sensor and an atmospheric pressure sensor.
As another example, an “activity level history storage device” in JP-A-10-318779 determines an amount of physical activity (calorie consumption) from an intensity of activity calculated from a movement detection signal.
Still another example includes a “calorie consumption measuring device” in JP-A-2003-93372 and WO1997/047239 which calculates a calorie consumption from a heart rate according to a regression equation when the user is at rest or exercising.
Further, a “health management system” described in JP-A-2005-115799 determines a state of activity from biological information obtained from sensors and changes a calculation process accordingly.
These conventional technologies, however, have a problem of not being able to determine the calorie consumption correctly because they do not consider a metabolism in a body. More specifically, in a recovery process following a physical activity of the user, the conventional technologies cannot detect a state in which the metabolism is at an elevated state (post-activity metabolic state), failing to calculate the calorie consumption with high precision.